In the control of paraventricular nucleus activity we have discovered a monoamine inhibitory system. Thus stimulation of the afferent pathway of the milk ejection reflex is without effect on either milk release or nuclear activity until reserpine is given in the unanesthetized rabbit. Characteristics of the anti-dromic activation of these cells is unaffected by this or any other drug regimen. The presence or absence of anesthesia effects a reciprocal system which probably involves the supra-optic nucleus. Thus, transsynaptic activation of paraventricular cells is not seen following hypothalamic- hypophyseal stimulation in the anesthetized rabbit but is seen in the unanesthetized preparation. In studies of the glucostatic hypothesis of hunger regulation we have been looking at the effects of 2 deoxy-d-glucose has on food intake when administered by different routes. Compared to jugular vein infusion the same quantity of 2DG given hepatic-portally induces significantly more eating with significantly shorter latency. In the sub-diaphragmatically vagotomized rabbit the amounts and latencies are like the rabbit infused through the jugular vein even though the administration is portal. Thus we feel we have evidence for a hepatic glucoreceptor system which conveys information to the CNS via the vagus nerves and is important in hunger regulation.